The restriction enzymes of bacteria protect the bacteria from successful attack by bacteriophages, whose genomes can be degraded by the restriction enzymes. The bacterial genomes are not vulnerable to these restriction enzymes because bacterial DNA is methylated. This situation selects for bacteriophages whose genomes are also methylated. As new strains of resistant bacteriophages become more prevalent, this in turn selects for bacteria whose genomes are not methylated and whose restriction enzymes instead degrade methylated DNA. Over the course of evolutionary time, what should occur?

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This scenario describes an evolutionary arms race between bacteria and bacteriophages, where both parties adapt over time to counter each other's defenses. This dynamic interaction would likely result in fluctuating populations of methylated and nonmethylated strains among both bacteria and bacteriophages, rather than the fixation of one type of DNA in either group.

The Restriction Enzymes of Bacteria Protect the Bacteria from Successful